This farthest galaxy cluster observed from Earth is discovered by astronomers from the U.S., Europe and Chile.
Almost 10 billion light-years from Earth, cluster XMM-XCS 2215-1734 contains hundreds of galaxies surrounded by hot X-ray-emitting gas. The existence of the cluster so early in the history of the universe challenges ideas about how galaxies formed, said lead author Adam Stanford, a research scientist at UC Davis and the Lawrence Livermore National Laboratory.
A student at Carnegie Mellon University determined the mass of this galaxy is 500 trillion times the mass of the Sun by using the temperature of the emitting gas. Most of the mass is “dark matter,” a mysterious, invisible form of matter that dominates the mass of all galaxies in the universe.
The European X-ray Multi Mirror (XMM) Newton satellite is used by the XMM Cluster Survey (XCS) team to discover the cluster and then determined its distance from Earth using the 10-meter W.M. Keck telescope in Hawaii. The team is working on a long-term observing program to find hundreds more such clusters using telescopes around the world.
